clear

Clear the screen

$ clear

$ clear -x

$ clear -T [type_of_terminal]

$ clear -V

clear [-x]

-x
    Prevents clearing the scrollback buffer, affecting only the visible screen area. Useful for retaining command history.

The clear command is a simple yet essential Unix utility that erases all content from the terminal screen, repositioning the cursor to the top-left corner. It leverages the terminal's capabilities via the terminfo database (or termcap in older systems) to issue the appropriate escape sequences, such as CSI 2 J (clear entire screen) and CSI H (cursor home) for ANSI-compatible terminals. This ensures a blank display without scrolling artifacts.

By default, clear attempts to clear both the visible screen and the scrollback buffer in modern terminal emulators like xterm, GNOME Terminal, or tmux, using operating system commands or escape sequences (e.g., OSC 3 for scrollback). This behavior prevents users from scrolling back to previous output, providing a true fresh start.

It's commonly used interactively to declutter the screen during long sessions, in shell scripts to improve readability, or bound to hotkeys (e.g., Ctrl+L in bash). The command is extremely lightweight, with negligible performance impact, and is available on virtually all POSIX-compliant systems. Its output depends on the $TERM environment variable; mismatches can lead to incomplete clearing.

Scrollback clearing relies on terminal emulator support (e.g., xterm, kitty); fails silently on basic terminals without scrollback. Incorrect $TERM may cause partial clears or garbage output.

clear
Clears screen and scrollback buffer.

clear -x
Clears visible screen only.

Queries terminfo for clear capability; defaults to ANSI \E[2J\E[H or equivalent.

Originated in early UNIX (pre-4.3BSD); POSIX.1-2008 standardized. Evolved with ncurses/terminfo for better terminal handling; minimal changes over decades due to simplicity.

reset(1), tput(1)